Saw an interesting GT3 at the track today...
08-07-2008, 01:30 AM
#46
Three Wheelin'
Colby,
For 100g's just do the math.
25 mph is about 36.66 feet per second, let's even round down and call this 36 feet per second.
One g is 32 feet per second per second (no typo, it's acceleration, not a velocity, so it's units are distance/(timeXtime) ) so 100 g's is 3200 feet per second per second.
So to slow down from 36 feet per second it takes .01125 seconds (=36/3200).
In this time you travel 18 X .01125 = .2025 feet because at the end of the deceleration you're going 0 feet per second and you started at 36 so 18 is the average speed for the .01125 seconds.
So if you stop from 25 mph in .2025 feet = 2.43 inches you will experience 100g's (and you could die). This is why you try not to hit things that are solid and also why we have crumple zones.
You haven't even done your first DE so the TE bar is probably ok. I also totally understand why you wouldn't want a full cage, however below is some food for thought about why a custom roll bar might be better than a TE bar. This is just in case you're interested in a compromise between the TE bar and a cage.
If you look through your windshield and slowly scan your eyes right until you see something that is metal, this is your right a-pillar. The TE bar runs near the b-pillar. I got a quote from TCD for a full cage that was less than 3x the cost of a TE bar so I can't imagine that a custom roll bar is much more expensive than a TE bar (maybe be less than 2x). The custom roll bar would be better than the TE bar because of better mounting, thicker tubing and more crossing support. Finally since it's a custom job the loop can be fabbed closer to your sunroofless roof (te bar designed to work with sunroof cars too I think) so that if the a-pillar collapses you'll have more room by being supported by the front of the car/dash and the b-pillar/(higher)roll bar. Make sense?
For 100g's just do the math.
25 mph is about 36.66 feet per second, let's even round down and call this 36 feet per second.
One g is 32 feet per second per second (no typo, it's acceleration, not a velocity, so it's units are distance/(timeXtime) ) so 100 g's is 3200 feet per second per second.
So to slow down from 36 feet per second it takes .01125 seconds (=36/3200).
In this time you travel 18 X .01125 = .2025 feet because at the end of the deceleration you're going 0 feet per second and you started at 36 so 18 is the average speed for the .01125 seconds.
So if you stop from 25 mph in .2025 feet = 2.43 inches you will experience 100g's (and you could die). This is why you try not to hit things that are solid and also why we have crumple zones.
You haven't even done your first DE so the TE bar is probably ok. I also totally understand why you wouldn't want a full cage, however below is some food for thought about why a custom roll bar might be better than a TE bar. This is just in case you're interested in a compromise between the TE bar and a cage.
If you look through your windshield and slowly scan your eyes right until you see something that is metal, this is your right a-pillar. The TE bar runs near the b-pillar. I got a quote from TCD for a full cage that was less than 3x the cost of a TE bar so I can't imagine that a custom roll bar is much more expensive than a TE bar (maybe be less than 2x). The custom roll bar would be better than the TE bar because of better mounting, thicker tubing and more crossing support. Finally since it's a custom job the loop can be fabbed closer to your sunroofless roof (te bar designed to work with sunroof cars too I think) so that if the a-pillar collapses you'll have more room by being supported by the front of the car/dash and the b-pillar/(higher)roll bar. Make sense?
A custom half cage from Tony is $2500 installed and painted. I can't imagine a full cage being less than $3500 painted and installed? A TE bar is 1k and you can find used ones at $600-$700.
08-07-2008, 01:43 AM
#47
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I would never have these issues with the C4..LOL
08-07-2008, 01:47 AM
#48
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Colby,
Thanks for the pricing info. Let's just say my quote was very fair and I hope it hasn't changed since I asked a year ago. Also there may be a little difference in pricing from GT3 and 930. If there is, it's not much and probably less than the price differences on other stuff. (my car is much older and I'm much poorer, I'd hope a cage is a bit cheaper).
Again, you're just starting to race so I wouldn't worry about more than a TE bar for now. But if you really get into it, the $2500 will be small compared to other racing expenses. Plus TE bars seem easy to sell, so you'll get your money back.
I'm assuming you already have a TE bar?
BTW you'll have to post after your first day in the GT3. It's a very cool car for to start with.
Thanks for the pricing info. Let's just say my quote was very fair and I hope it hasn't changed since I asked a year ago. Also there may be a little difference in pricing from GT3 and 930. If there is, it's not much and probably less than the price differences on other stuff. (my car is much older and I'm much poorer, I'd hope a cage is a bit cheaper).
Again, you're just starting to race so I wouldn't worry about more than a TE bar for now. But if you really get into it, the $2500 will be small compared to other racing expenses. Plus TE bars seem easy to sell, so you'll get your money back.
I'm assuming you already have a TE bar?
BTW you'll have to post after your first day in the GT3. It's a very cool car for to start with.
08-07-2008, 02:10 AM
#49
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Mooty,
I've been having withdrawal symptoms since my last track day was May I think. My Porsche is still with Stephen Kaspar at ImagineAuto and my Subaru needs a tranny cooler before it can go back to the track. I suppose I could take the old e30 again...
So I'll have to wait to shoot the breeze with you guys until I have something I'm able to drive. I would like to see TCD's work as soon as I get my Pcar back.
So tell me if I'm crazy...
I know the car is going to see enough track time and be enough of a handful that I want a full cage in it for safety and to be a solid chassis for coil overs. However, I still want to drive it on the street. I don't mind loud brakes and I'm going to put in a lightweight felt interior so it shouldn't be that terrible inside. That and I'm not going to go too crazy on the spring rates (450/600).
I noticed that Ruf had many integrated roll cage street cars and the work I've seen by TCD online has been pretty good. So if I have all the trim removed and get the bar as close as possible to the metal a-pillar and roof, then cover it with the real high quality, engineered to absorb energy, padding could this be that much worse for street safety?
Con: Well fabbed tube closer to head, however since the tube is hopefully RIGHT next to a-pillar and roof, metal should be closer to my head by less than 2 inches.
pro: specialty energy absorbing padding should do better in an accident than interior trim and of course the car will be more structurally sound.
I know JackOlsen runs a cage on the street, so with the right precautions, is it that crazy/dangerous compared with no cage on the street?
I've been having withdrawal symptoms since my last track day was May I think. My Porsche is still with Stephen Kaspar at ImagineAuto and my Subaru needs a tranny cooler before it can go back to the track. I suppose I could take the old e30 again...
So I'll have to wait to shoot the breeze with you guys until I have something I'm able to drive. I would like to see TCD's work as soon as I get my Pcar back.
So tell me if I'm crazy...
I know the car is going to see enough track time and be enough of a handful that I want a full cage in it for safety and to be a solid chassis for coil overs. However, I still want to drive it on the street. I don't mind loud brakes and I'm going to put in a lightweight felt interior so it shouldn't be that terrible inside. That and I'm not going to go too crazy on the spring rates (450/600).
I noticed that Ruf had many integrated roll cage street cars and the work I've seen by TCD online has been pretty good. So if I have all the trim removed and get the bar as close as possible to the metal a-pillar and roof, then cover it with the real high quality, engineered to absorb energy, padding could this be that much worse for street safety?
Con: Well fabbed tube closer to head, however since the tube is hopefully RIGHT next to a-pillar and roof, metal should be closer to my head by less than 2 inches.
pro: specialty energy absorbing padding should do better in an accident than interior trim and of course the car will be more structurally sound.
I know JackOlsen runs a cage on the street, so with the right precautions, is it that crazy/dangerous compared with no cage on the street?
08-07-2008, 02:16 AM
#50
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Interesting analysis, and i dont quite follow. Probably b/c i was never good with math. But since you're on a PhD Physics program i'll take your word for it.
A custom half cage from Tony is $2500 installed and painted. I can't imagine a full cage being less than $3500 painted and installed? A TE bar is 1k and you can find used ones at $600-$700.
A custom half cage from Tony is $2500 installed and painted. I can't imagine a full cage being less than $3500 painted and installed? A TE bar is 1k and you can find used ones at $600-$700.
08-07-2008, 02:19 AM
#51
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Mooty,
I've been having withdrawal symptoms since my last track day was May I think. My Porsche is still with Stephen Kaspar at ImagineAuto and my Subaru needs a tranny cooler before it can go back to the track. I suppose I could take the old e30 again...
So I'll have to wait to shoot the breeze with you guys until I have something I'm able to drive. I would like to see TCD's work as soon as I get my Pcar back.
So tell me if I'm crazy...
I know the car is going to see enough track time and be enough of a handful that I want a full cage in it for safety and to be a solid chassis for coil overs. However, I still want to drive it on the street. I don't mind loud brakes and I'm going to put in a lightweight felt interior so it shouldn't be that terrible inside. That and I'm not going to go too crazy on the spring rates (450/600).
I noticed that Ruf had many integrated roll cage street cars and the work I've seen by TCD online has been pretty good. So if I have all the trim removed and get the bar as close as possible to the metal a-pillar and roof, then cover it with the real high quality, engineered to absorb energy, padding could this be that much worse for street safety?
Con: Well fabbed tube closer to head, however since the tube is hopefully RIGHT next to a-pillar and roof, metal should be closer to my head by less than 2 inches.
pro: specialty energy absorbing padding should do better in an accident than interior trim and of course the car will be more structurally sound.
I know JackOlsen runs a cage on the street, so with the right precautions, is it that crazy/dangerous compared with no cage on the street?
I've been having withdrawal symptoms since my last track day was May I think. My Porsche is still with Stephen Kaspar at ImagineAuto and my Subaru needs a tranny cooler before it can go back to the track. I suppose I could take the old e30 again...
So I'll have to wait to shoot the breeze with you guys until I have something I'm able to drive. I would like to see TCD's work as soon as I get my Pcar back.
So tell me if I'm crazy...
I know the car is going to see enough track time and be enough of a handful that I want a full cage in it for safety and to be a solid chassis for coil overs. However, I still want to drive it on the street. I don't mind loud brakes and I'm going to put in a lightweight felt interior so it shouldn't be that terrible inside. That and I'm not going to go too crazy on the spring rates (450/600).
I noticed that Ruf had many integrated roll cage street cars and the work I've seen by TCD online has been pretty good. So if I have all the trim removed and get the bar as close as possible to the metal a-pillar and roof, then cover it with the real high quality, engineered to absorb energy, padding could this be that much worse for street safety?
Con: Well fabbed tube closer to head, however since the tube is hopefully RIGHT next to a-pillar and roof, metal should be closer to my head by less than 2 inches.
pro: specialty energy absorbing padding should do better in an accident than interior trim and of course the car will be more structurally sound.
I know JackOlsen runs a cage on the street, so with the right precautions, is it that crazy/dangerous compared with no cage on the street?
but i know jack olsen and another person who drives fully caged car to/from track and race them. they seem to be fine.
for ME. if i caged my car, i will only drive it to/from track and mechanics, i would not drive it on street unless i have to. just minimize unnecessary risk.
08-07-2008, 04:19 AM
#52
Three Wheelin'
Colby,
Thanks for the pricing info. Let's just say my quote was very fair and I hope it hasn't changed since I asked a year ago. Also there may be a little difference in pricing from GT3 and 930. If there is, it's not much and probably less than the price differences on other stuff. (my car is much older and I'm much poorer, I'd hope a cage is a bit cheaper).
Again, you're just starting to race so I wouldn't worry about more than a TE bar for now. But if you really get into it, the $2500 will be small compared to other racing expenses. Plus TE bars seem easy to sell, so you'll get your money back.
I'm assuming you already have a TE bar?
Thanks for the pricing info. Let's just say my quote was very fair and I hope it hasn't changed since I asked a year ago. Also there may be a little difference in pricing from GT3 and 930. If there is, it's not much and probably less than the price differences on other stuff. (my car is much older and I'm much poorer, I'd hope a cage is a bit cheaper).
Again, you're just starting to race so I wouldn't worry about more than a TE bar for now. But if you really get into it, the $2500 will be small compared to other racing expenses. Plus TE bars seem easy to sell, so you'll get your money back.
I'm assuming you already have a TE bar?
As such, I'm really starting to understand RL now. Its more of a closed community to those with track experience. If you dont have it, dont comment or be prepared for a lot of arrogant useless comments aimed at putting you in your 'place' and reminding everyone on this board of your newbie status. And like i said frankly i'm tired of hearing it. I think A LOT of the more track experienced members take a great deal of pride in putting newbies in their place instead of welcoming them. Comes with the territory i suppose. I've gotten all i need from RL (mainly contacts like Mooty, CJ, Dan, etc...), as well as many outside enthusiast and tuners who can help guide my track time, spending, instruction, etc...so in a short while i'm going to give posting on RL a rest. At least until i have more track experience so i dont have to deal with the arrogance.
But we can chat in person at CAL if you like.
Best,
08-07-2008, 12:36 PM
#54
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08-07-2008, 01:07 PM
#55
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Colby,
Calling us arrogant won't make you friends.
Many of us are professionals that deal with data. We don't make assumptions about anything. Assumptions can lead to poor decisions.
Allot of misinformation gets posted on the net. RL is not a place that takes kindly to this.
Calling us arrogant won't make you friends.
Many of us are professionals that deal with data. We don't make assumptions about anything. Assumptions can lead to poor decisions.
Allot of misinformation gets posted on the net. RL is not a place that takes kindly to this.
08-07-2008, 01:15 PM
#56
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U mean Laguna Seca no doubt? And you were sideways after turn 1? I did the Skip Barber hi performance school there and we drove 996 and 997 Porsche as well as the Boxsters. I cannot imagine what you must have done to get loose there. Did you lift as you crested? Even when we had a few hot laps with the Skip barber boys driving we never got loose on turn 1.
sorry, this may appear to be off topic..
08-07-2008, 02:41 PM
#57
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I think eric was in stock 996 on his first few days out.
Were u at FULL throttle to T1? I'm wot until market 4. If u aren't at the right spot u will get loose on top of hill at wot.
Were u at FULL throttle to T1? I'm wot until market 4. If u aren't at the right spot u will get loose on top of hill at wot.
08-07-2008, 05:39 PM
#58
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A couple comments on the cage/TE bar question... A TE bar provides roll protection and maybe a bit of protection if you take a hit right on it from the side. A cage provides protection from all angles, especially a side impact. I used to run with a bolt-in cage that had been welded in place. I saw too many accident to feel safe with it so I had Tony build a full custom cage last winter. I started DE with a DAS rollbar in a cabriolette, but once I started going faster i wanted the additional protection of a cage (and so I bought the Turtle).
In a way you can argue a TE bar provides no protection - it doesn't do anything for a frontal impact and not much if you get t-boned because you spun and the guy behind could not stop. Hopefully the driver at least uses a HANS device or equivalent too.
Eric and John - looking forward to seeing you black sheep next week. I'll run at 4/10 so John can keep up.
In a way you can argue a TE bar provides no protection - it doesn't do anything for a frontal impact and not much if you get t-boned because you spun and the guy behind could not stop. Hopefully the driver at least uses a HANS device or equivalent too.
Eric and John - looking forward to seeing you black sheep next week. I'll run at 4/10 so John can keep up.
08-07-2008, 07:58 PM
#59
Three Wheelin'
Understandably, but why would i want to make friends with guys who take pride in flaming a newbie? And FWIW i wasnt referring to the general GT3 body. As you know one egg can ruin the lot.
I'm not sure how this pertains to my comment? I never said anything about bad assumptions?
I'm not sure how this pertains to my comment? I never said anything about bad assumptions?
08-07-2008, 07:59 PM
#60
Three Wheelin'
